Getting to the bottom of it

A wide range of factors plays a part in what happens underneath says Jessica Doyle of Jotun. This includes water quality, temperature, salinity and the depth of the berth. So you probably need to be nosey and ask your customers where they are going and what they intend to be doing as it makes a big difference.

Ms Doyle goes on to say that although the present products do offer the same advantages and features as the previous tributyltin (TBT) products, ‘it generally comes at a higher initial cost’. So matters of economy also enter the mix.

For example, both Jotun’s Mare Nostrum SP and NonStop ranges are based on a hydrating, eroding formula. Ms Doyle explains, ‘While this is cheaper than the self-smoothing Imperial AF from the Megayacht range, it is perfectly adequate for smaller boats that get taken out every year.’ For cost-conscious boater, an added advantage is that it can be put on as a DIY project, while the Megayacht coatings can only be professionally applied.

Advances
But even if generally a little more expensive, advances in self polishing/self smoothing technology have helped. Michael Hop, general manager of Seajet says that the company’s best known products rely on hydrolysis: this comes about from the splitting of polymers into smaller molecules. It is a different process to the eroding antifoul coatings which rely on hydration, and tend to leave a chalky ‘leached’, used up layer.

But it is not the whole answer. Mr Hop explains that although the ebb and flow of the tide still ensures that self-polishing products work, performance is lessened if a boat is left standing for months on end. He goes on to say yachts that dry out at low tide need a hard antifoul, such as Seajet’s 037 Coastal – and not one of the hydrolysing, self polishing types which, by their very nature, are soft.

Ms Doyle concurs, and adds that hard products do provide an excellent result for boats with long mooring periods or berthed in tide areas where a high abrasion resistant product is needed to withstand impact against the sea or river bed.

Motorboats
Making things slightly more complicated, while sailing boats are ideally suited to self polishing antifouls, the varying speeds of motorboats can make for problems –too soft a product won’t last the season.

Thin film antifoulings, like the VC range from International, Seajet’s 037 or Jotun’s Racing Ultraspeed, and 'hard' antifoulings such as International's Interspeed Ultra and Jotun's Racing have been formulated to be extremely durable – International uses Teflon - while also resisting ‘chalking’ or degrading to a rough surface. However, these tend to be a ‘one season’ finish, and unless your customers are really keen on keeping their speed up, they might find it easier to work with other self-polishing versions.

Given all this, getting it right for any one motorboat in a particular situation is still, it seems, a process of trial and error.

Warmer… and colder
There’s also the question of temperature. Obviously, the warmer soup of the med means more growth, but particular needs may vary – and there’s that cost implication again.

For example, while Seajet has developed the 039 Platinum to work across a range of temperatures, making it ideal for ‘blue water’ cruisers who may split their time between the Caribbean and northern Europe for example, it is top of the company’s range – and its most expensive product.

At the other end of the temperature spectrum, care is still needed. Low seawater temperatures combined with wide variations in sunlight, from 0-24 hours a day, require a particular self-polishing formulation, like Jotun’s Sea Omega.

Also aimed at more northerly markets, Seajet’s 034 Emperor antifoul has had its chemical performance optimised for low temperatures, adjustments made to the cold-water leaching rate and has also been made easier to apply in the very cold conditions of Norway and Sweden.

On the other side, there is the market for antifouling specifically designed for fresh water areas and inland waterways - like International’s Waterways Plus, a hard and scrubbable product.

Long term protection
Marine Technology, the manufacturers of CuNiGuard, believe they have at least part of the answer to the ongoing chore and environmental considerations. A single application can provide more than ten years of protection against marine growth and biological infestation, yet without the release of harmful biocides into the environment – the product has a low leaching rate and so, says the manufactures, it has a minimal impact (and is fully compliant with UK and EU law).

It is a process that combines the traditional antifouling characteristics of copper with the durability of nickle. A complete layer of copper nickel is professionally sprayed onto a specially formulated epoxy resin base coat - the epoxy base coat lies completely beneath the outer copper nickel layer and results in an even surface coverage that provides total protection.

The average cost of using CuNiGuard is calculated at around £65 per square metre – ‘not cheap,’ admits the company. However, because a single application will last for many years and will also eliminate the need for regular hoisting-out and re-launching, the long term cost savings to boaters can be substantial.

Compliance costs
Michael Hop says the legal environment is having an impact on manufacturers, as they now have to conform with the Biocide Products Directive (BPD) which aims to eventually harmonise the market for biocidal products and their active substances. ‘The responsibility for adhering to the directive lies with the producers and formulators, who must apply for authorisation by submission of a dossier containing the relevant materials such as scientific studies,’ he explains.

‘This is a costly business and one that has and will continue to have a bearing on the growth of smaller manufacturers, who already have and will continue to be discouraged in launching specialist products that sell in smaller numbers.’

Seajet, though, is in an interesting position in the market: the company is large enough to have the resources for serious research and product launches, while at the same time is still small enough to be able to come up with customised formulations – although admittedly not for the ‘occasional’ can, it is something that makes an impact given a slightly different market or a boatbuilder who wants to tie in a whole bespoke range.

Interestingly, this willingness to enter into batch requests also helped out Northshore Yachts. The boatbuilders knew exactly what they wanted for their distinctive Southerly range – and although the technical formulation was right, it wasn’t a standard colour. So Seajet customised a particular grey especially for them.

Good vibrations
On the other hand, away from the coatings angle entirely, Ultrasonic Antifouling uses high frequency and virtually inaudible low power sound waves to destroy algae - prevent the algae from attaching itself on to the hull and you stop weed growth and the base for barnacles.

The company currently offers two models with either one or two transducers (bespoke systems can be designed for superyachts or trimarans etc). These create a wall of moving water molecules over the whole surface of the submerged hull, creating a micro-environment that kills algae and prevents barnacle growth.

The system covers all of the hull and underwater gear including propeller, shaft and sterngear, water intakes, bow thruster, log impeller, trim tabs, sail drive and outdrives - though careful placement of the transducers is the key to success. Giving extra value, this digital (as opposed to older analogue) systems can use a wider range of frequencies, so killing algae more effectively – and be reprogrammed and updated.

However, ‘Refreshing the antifoul would still be a good idea every few years – not from a toxicity point of view but more just from protecting a boat’s bottom,’ says Bob Evans of Ultrasonic.

The system retails for around £1,000 but, as Mr Evans says, ‘it is a one off cost’, and compares very favourably with the money needed for yearly treatments.

Environmental note
But despite the new technology, Brian Clark of the BMF remains realistic about cleaning up entirely, at least at present, saying it is often a balance between increased fuel consumption from drag and the relative toxicity of the coatings. He explains. ‘What you have to understand is that there is no such thing as yet as totally environmentally friendly antifouling if it includes biocides.’ The ban on TBT’s resulted in a plethora of different products, but most have copper in some form and copper is also toxic, ‘it has to be to work,’ adds Mr Clark

Obviously, there are other alternatives like dry stacking, which keeps the need for antifoul down to a minimum, but in Mr Clark’s view, if people keep their boat in a marina, some kind of antifouling system is needed to keep its bottom clean.